Contamination such as glass in filled containers (with drink such as beer intended for consumption), such as bottles, can be hazardous in the case of human consumption, and in the case of a claim will in any case damage the brand reputation of a supplier.
In a known in-line machine bottles are measured at a number of locations, wherein the bottle is rotated 90° on its vertical axis using a mechanism to enable different views to be realized. This makes the machine relatively large and mechanically complicated. The different inspection units (=cameras) only co-act at the logical level in the decision as to whether or not the bottle must be rejected. If one inspection unit detects contamination, the bottle is rejected. If no inspection unit detects contamination, the bottle is not rejected. This has the drawback that each inspection unit separately must be set with its own rejection threshold. Furthermore, in order to prevent dubious cases and false reject, each inspection unit cannot be given a very sensitive setting. This known machine is hereby not very sensitive and small contaminants cannot be detected (false accept). If however the system is set to be sensitive, a very great deal of false reject then occurs. Glass particles smaller than about 3 mm are generally not visible.
In other machines bottles are irradiated with high-energy (X-)radiation. This can in fact have harmful consequences, and has in any case the association of undesirable influencing of the product for inspecting. In addition, the cost of an X-ray source and detector are relatively high. The basic system will hereby be expensive. In addition, there is a physical limit to the measure of detection because X-ray is based solely on measuring a difference in absorption of rays. Glass particles smaller than about 3 mm are generally not visible.
In other known methods the bottle is actively rotated. The possibility of detecting smaller particles hereby increases, but the embodiment as carrousel requires a complex mechanical set-up which is therefore inherently expensive. A typical number of heads in a carrousel machine is for instance 30 to even 45+24 heads in a 2 star wheel configuration.